What do you think is the most important power granted to the president? why?

The power to Veto any law trying to be passed. It helps keep Congress from going wild with laws, by using a power in its self-called Checks and Balances. (Of course, Congress can override a veto, but it takes a super-majority vote, which is not very easy to do)...

Summarized from a U.S. Government Class POV / Wiki entry: It's all part of the "checks and balances" of the US government. No one branch out of the three has too much power, and the other two have their ways to prevent any branch from getting too much power.

The changes to agriculture in the united states since 1900 is that increased mechanization has increased food production, thereby increasing the need for labor. there has been an increased need for higher speeds of food production due the fact that the population in the united states continues to rise.